Extreme pressure lubricant



Patented Feb. 17, 1953 EXTREME PRESSURE LUBRICANT Elmer B. Cyphers,Cranford, and Walter E. Waddey, Elizabeth, N. J assignors to StandardOil Development Company, a vcorporation of Delaware No Drawing.Application February 3, 1949,

Serial No. 74,483

2 Claims.

1 I This invention pertains to extreme pressure lubricant-s andcompositions for imparting extreme pressure or load-carrying propertiesto lubricating oils. The invention also pertains to .a method forpreparing extreme pressure agents,

incorporating elements such as sulfur, phosphorus, and the like, in sucha manner that they will be available for suitable chemical activityunder heavy load conditions.

As is well understood in the art, ordinary mineral base lubricating oilsand greases which are used to lubricate opposed metal surfaces arelikely to fail under extreme heavy load conditions. For example, certainmachine elements such as the hypoid gears commonly used in automotivevehicles may be subjected at time to extremely heavy pressures of theorder of hundreds of thousands of pounds per square inch. If the film oflubricating oil separating the opposed elements fails, as it is likelyto do under such pressure, the surfaces will contact each otherdirectly, generating high temperatures due to friction, with resultantseizure or excessive wear and early failure. Extreme pressure additivescontaining active sulfur, phosphorus, or chlorine, or two or more ofthese, are effective for reacting immediately with the metal surfaces attheir higher temperatures to form a protective metal sulfide, phosphide,or chloride film Which serves temporarily as a, lubricating medium untilthe normaloil film between the parts can be reestablished. Extremepressure additives -are,-.th-erefore, reactive with the metals theylubricate to form extremely thin protective films thereon when thetemperature rises due to normal oil film failure. It is known in the artthat good extreme pressure lubricants may be produced by adding tomineral base lubricating oils and greases sulfur-chlorine additives ofthe type described in U. S. Pat. No. 2,124,598.

Lubricants containing this type of additive are excellent for thelubrication of hypoid gears subjected to low-torque, high-speedconditions, such as the hypoid gears usedon passenger carryingautomotive vehicles but are not well suited for use under high-torque,low-speed conditions, such as are found in heavy truckoperations. It isalso known that sulfurized and phosphorized esters of rosin acids of thetype described in copending application Serial No,

2 712,050 filed November 25, 1946, now Patent No. 2,488,618, issued Nov.22, 1949, in the names of E. B. Cyphers and G. M. McNulty, yieldlubricants especially suitable for use in high-torque, low-speedoperations, but only moderately effective under low-torque, high speedconditions. It is an object of our invention to provide, in a singleadditive, the excellent high speed properties of the sulfur-chlorinetype additive and the excellent high-torque properties of thesulfur-phosphorus-ester type additive.

While this may be accomplished by mixing, in suitable proportions, thetwo types of additives, such a blend is not well suited for use in mostmineral oil base stocks, because such a mixture has a severe depressingeffect on the viscosity index of the oil to which it has been added.Often, this depression of viscosity index is so severe that theresulting composition has little or no utility in lubricating practiceunless mineral oils of very high viscosity index are readily available.

According to the present invention, it has been discovered thatcompositions having excellent extreme pressure properties, under bothhigh speed and high-torque conditions, and avoiding viscosity indexdepression, may be obtained by blending with the base stock anadditional or third component comprising sulfurized, or sulfurized andphosphorized fatty bodies, sulfurized fatty bodies containing nophosphorus being preferred. The fatty body containing sulfur alone ispreferred for the reason that a blend containing said fatty bodyexhibits superior load-carrying capacity compared with a blendcontaining a sulfur-ized and phosphorized fatty body.

It is also possible to prepare lubricants of considerable merit fromphosphorized esters of rosin containing little or no sulfur mixed withsulfurized fatty bodies containing no phosphorus, and with thesulfur-chlorine products previously described. The phosphorized rosinesters in such a mixture may be prepared by treating the esters WithP483, P437, P2S5, PCLs, P205, and

and a halogen, prepared by reacting a halogenated compound having analiphatic chain with an inorganic sulfur salt so as to replace only aportion of the halogen with sulfur; an example is a sulfur andchlorine-containing compound prepared by the reaction of chlorinatedaliphatic acids, esters, or hydrocarbons with an alkali or alkalineearth metal sulfide or polysulfide;

b. Rosin acids, esters, alcohols, abietic acids and esters, hydrogenatedderivatives of rosins and abietic acids and esters and alkylsubstituents of hydrogenated and unhydrogenated rosins and abietic acidsand esters, containing phosphorus or phosphorus and sulfur.

Specific examples of rosin derivatives which may be employed are: methylabietate, methyl ester of rosin acids, abietic acidestersof ethyleneglycol, glycerol, octanol, and isopropanol, es-- ters of dihydroabietylalcohol, dextropimeric acid and the like.

0. Sulfurized and phosphorized fattyoils,-acids, esters, and other fattybodies. Ormore particularly, sulfurized fatty oils, acids, esters, andother fatty bodies. Specific examples of fatty bodies which may beemployed include: sperm oil, lard oil, methyl oleate, degras isopropyloleate, cottonseed-oil, corn oil, peanut-oiI-and the like.

In producing the lubricating oil blend of the present invention, theadditive materials, which individually per se do not 'form a part :ofthe invention, are :preparedby any of the methods described. in the :artcited above.

Thus, in one examplenthe sulfur and-chlorine= containing. material wasprepared 'by bubbling chlorine gas through a mixturecontaining about 40%paraffinwax: and-60% "kerosene to produces,

chlorinated mixture containing about 37% chlorine; 'This wasthencondensedwithsodium polysulfide by: refluxing in an alcohol'icsolution until all-of the alkalinepolysulfide had reacted. "The alcoholwas thenremoved by distillation under vacuum and the product filteredandwashedwith an aqueous caustic solution :to reduce its corro-'siveness toward copper, the final product containing 6 .0%sulfur and30.3% chlorine,

The sulfur and phosphorus-containing rosin derivatives may be preparedfrom a commercial grade of methylatedkrosin produced byesteri-fi'ca-.tion of rosin with methyl alcohol and commercially known. as Abalyn.Suitable conditions for sul-iurizi-ng :arebyheating withsu'lfur at atemperature in the range from about 250 'F. to

about'500'F. The-sulfurized product,or in some cases-the unsulfurizedrosin ester, isphosphorized by heating with a bi-elemental phosphoruscompound, for example, P483, Pass, P4$7{P2O5,'8l10.,l30 atemperaturzbetween 150 and 300 F.,-pr.eferablyvbetween200" and250 F.,Jfor:asuitable time such ,25 2.20 hours until a product, which doesnot'bla'cken copper when tested in a 10% concentration inmineral oil forone hour at 250 l is obtained.

Thefatty-body is'prepared by reacting it with from.;3 to 12%,preferably6 by Weight of sulfur ata temperature of ..250.-500 F. until anon-corrosivev product, as defined above, is obtained. If phosphorizingalso is desired, the sulfurized prodnut .is treated with a bi-elementalphosphorus compound-such 3.5 1 483, P4557, P285, P205, PCLs', etc;Preferably phosphorus sesquisulfide is used at atemperaturezbetween 150and 300 F.

The three additive materials are blended in varying proportions,depending on the use to which the blend :is to be put.

The proportion of the sulfur and chlorine-consulfurized and phosphorizedfatty body 0 to yield a. mixture which has little or no viscosity indexdepressing effect, the preferred ratio being about 60:14.0. However,when some viscosity index improvement is required ratios as high as75:25 *maybe employed; and Where a mild viscosity index depressingeiiect can be tolerated, ratios as low .as 40:.60 ;may be used. Apreferred blend contains from 30 to 50% phosphorized and sulfurized.rosin or rosin acid derivative, 20% to 35% sulfurized (orsulfurized-phosphorized) fatty body and 20% to 50% sulfurized andhalogenated aliphatic compound. This blend *may be added to'lu'bricatingoils or greases in proportions ranging from 1.0 to20weight-percent'basedon total composition.

-Our invention wiil' be more fully understood by reference to thefollowing examples:

EXAMPLE .I

An extreme pressure-additive-was prepared by blending by weight:

Percent Pisa-treated sulfurized. Abal-yn 4-2 Sulfurized sperm .oil .28

Sulfur-chlorinecontaining wax-.kerosene-mix- .ture r Ten percent'byweight of this additivewas-blended withv an SAE '90grademineral-oilhaving the following characteristics:

Vie/10.0 SUS 939.3 Vie/210 sus 435.1 Vis. index. .95

The blended lubricant was 'testedpm the v.SAE

and .Timkemmachines accordingto the test procedures L's-.17 and-L48,respectively described in the Handbook of the Coordinating ResearchCouncil, Inc 1946 edition.

EXAMPLE ,-II

For comparison with Example I, an additive was blended from 42weight-percent Pisa-treated sulfurized Abalyn'. 28% P4Ss-treated'sulfurized sperm oil and 30% of a caustic-washed sulfur andchlorine-containing paraffin wax-kerosene mixture. A 10% blend ofthisadditive in .aSAE

mineral oil basestock was prepared andtested, with the results showninthe table.

EXAMPLE An additive containing .slightly difierent pro.- portions ofingredients was prepared: from Percent Piss-treated sulfurized Abalyn 39Risa-treated sulfurized sperm. oil '26 Sulfur-chlorinecontainingwax-kerosene mixture 35 A 10% mineral oil blend was tested as before,the data being shown in the table.

EXAMPLEIV An additive containing still different proportions ofingredients was prepared by blending Per cent Risa-treated sulfurizedAbalyn 30 Risa-treated sulfurized sperm oil 20 Sulfur-chlorinecontaining wax-kerosene mixture 50 This additive was also blended withmineral oil in concentration and testedas before, with the results shownin the table.

In addition to the data on the foregoing examples, the table includescomparable data on the performance of the ingredients of the additivemixtures. It will be noted that, in every example, the lubricants of ourinvention carry higher loads on the SAE machine than comparablequantities of any of the individual ingredients, and much higher thanwould be expected from an examination of the individual values weightedin proportion to the percentage of each in the mixture.

With regard to the Timken test data, it will be observed that the loadscarried by the lubricants of Examples 11, III and IV are approximatelyin the range which would be expected from a weighted average of thevalues obtained from the individual ingredients. However, in Example I,the lubricant carried a Timken load not only well in excess of theweighted average for the individual ingredients, but even greater thanthe best single ingredient (Pisa-treated sulfurized Abalyn) in the full10% concentration.

We have thus discovered a number of combinations of additivesexemplified by Examples II, III, and IV, which are superior inperformance to any of the individual constituents as measured by the SAEmachine. Since performance on this machine is widely accepted as anindication of performance in automotive gears under conditions oflow-torque and high-speed (passenger caroperation), these materials areshown to be unexpectedly useful for this type of service.

We have also discovered certain other combinations, exemplified byExample I, which not only perform with unexpected merit on the SAEmachine but also carry unexpectedly high loads on the Timken machine.Since the Timken performance is believed to be indicative of performancein hypoid gears under conditions of high-torque and low-speed (truckoperations), the latter type of additive is unexpectedly effective as anall-purpose lubricant for both passenger cars and trucks.

It is to be understood: of course, that conventional antioxidants,viSCosity index improvers,

and the like may be added to the lubricants of our invention, as will beobvious to those skilled in the art. It is also to be understood thatour invention is not limitedby any theory of operation or by theparticular examples cited, but only by the appended claims.

What is claimed is:

1. A lubricating oil additive material having the characteristic ofimparting desirable extreme pressure properties to "a lubricating oilwith which it is blended consisting of about 50% by weight of a reactionproduct of a chlorinated wax-kerosene mixture with sodium polysulfide,about 30% by weight of a Pisa-treated sulfurized methylated rosin, andabout 20% by weight of a Pisa-treated sulfurized sperm oil.

2. A mineral lubricating oil composition consisting essentially of amineral oil base stock containing combined therein about 10% by weight,based on the weight of the total composition, of a mixture comprisingabout 50% of a reaction product of a chlorinated waxkerosene mixturewith sodium polysulfide, about 30% by weight of a P483 treatedsulfurized methylated rosin, and about 20% by weight of a P483 treatedsulfurized sperm oil.

ELMER. B. CYPHERS. WALTER E. WADDEY.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS

1. A LUBRICATING OIL ADDITIVE MATERIAL HAVING THE CHARACTERISTIC OFIMPARTING DESIRABLE EXTREME PRESSURE PROPERTIES TO A LUBRICATING OILWITH WHICH IT IS BLENDED CONSISTING OF ABOUT 50% BY WEIGHT OF A REACTIONPRODUCT OF A CHLORINATED WAX-KEROSENE MIXTURE WITH SODIUM POLYSULFIDE,ABOUT 30% BY WEIGHT OF A P4S3-TREATED SULFURIZED METHYLATED ROSIN, ANDABOUT 20% BY WEIGHT OF A P4S3-TREATED SULFURIZED SPERM OIL.